非对称薄壁箱形截面的扭转几何特性研究

Research on torsional geometric properties of asymmetric thin-walled box section

为了揭示顶板单向横坡对薄壁箱形截面扭转几何特性的影响,推导了顶板为倾斜布置的非对称薄壁箱形截面扭转中心位置、主扇性坐标及主扇性惯性矩的实用计算公式。运用推导的实用公式并结合数值算例,比较顶板倾斜布置和水平布置对截面扭转几何特性的影响,并分析了顶板横坡、箱室高宽比及悬臂板宽度变化对扭转几何特性的影响规律。研究表明,本文计算值与有限元软件ANSYS中截面特性计算结果吻合很好;当不考虑顶板横坡时,对扭转中心横向位置及高腹板与底板交点处的主扇性坐标影响显著;当箱室高宽比小于0.65时,其变化对扭转中心的横向位置有显著影响;主扇性惯性矩随顶板横坡的增大而减小,随悬臂板宽度及箱室高宽比的增大而增大。

In order to reveal the effect of the cross slope on the torsional properties of asymmetric thin-walled box section with inclined top plate,the practical formulas for calculating the twist center,principal sector coordinate and principal sector moment of inertia of cross section were derived.Based on the practical formulas,the effects of torsional geometrical properties between the inclined and horizontal top plate were compared,and the influences of the variations of the cross slope,cell height to width ratio and cantilever plate width on the torsional properties were analyzed.The research shows that the results in this paper are in good agreement with those computed by the finite element software ANSYS.When the cross slope is not considered,the lateral position of the twist center and the principal sector coordinate at the intersection of the higher web and bottom plate will be significantly affected.When the cell height to width ratio is less than 0.65,its change has a significant effect on the lateral position of the twist center.The principal sector moment of inertia decreases with the increase of the cross slope,and increases with the increase of the cantilever plate width and cell height to width ratio.